Strategies for Doubling

How two-a-days can benefit non-elites

When I started my coaching career I was forced into having athletes run twice a day during the school year because we were limited to running all mileage on a 1.25-mile loop. As my first athlete, a former 4:14 high school miler, Jeremy Warren likes to say, "We ran doubles because it is physically impossible to run more than five loops during one run without needing to see a psychiatrist afterwards." Given this situation, as a coach I quickly and almost accidently found the benefits of doubles, even for non-elite athletes. For most adult runners, however, doubles are a foreign concept, assumed to be the province only of those cranking out 100-mile weeks.

I would like to convince you to think otherwise. Intelligently adding some double days to your program can help advance your fitness, even if you wind up not significantly increasing your mileage.

WHEN TWO RUNS BEAT ONE

Conventional wisdom has it that a longer single run should be better than any sort of split double run. But there are several circumstances in which two runs in a day are better than one.

During a base-training period, when you're trying to build general endurance, longer single runs provide the stimulus you're looking for. But once you've built your general endurance, the need for longer single runs every day shifts, for two reasons. First, it's easier to maintain endurance than to build it; therefore, as long as you have a regular long run and your overall mileage hasn't dropped considerably, you won't lose general endurance. Second, after your base phase the emphasis shifts to harder workouts, and more important, recovering from them. While it might seem counterintuitive at first, adding a second run can be used to enhance recovery and even to increase adaptation.

A common yet sometimes surprising result of including two runs in a day is that you often feel better and more recovered the following day. The most obvious reason is that by running shorter twice, you don't beat your body up as much as on a longer single run. On these shorter runs you have plenty of fuel stores and rely primarily on your heavily fatigue-resistant slow-twitch fibers. Result: No lingering fatigue or damage caused by these short runs. Instead, you get an increase in blood flow twice to help with recovery, and perhaps more importantly an increase in hormones, such as human growth hormone, that will help with recovery. Getting a nice hormonal spike to aid recovery twice during a day does wonders in getting you recovered for the next day's run or workout.

The benefits of doubles go beyond just recovery. One workout by itself doesn't translate to a sudden increase in fitness. Instead, each run triggers the body to signal certain genes to make functional adaptations. It takes multiple runs or workouts to translate that signal into some sort of functional change. Essentially, you need an accumulation of stimuli to get the training adaptations you work so hard for.

Doubling plays a role in this in two ways. First, even though each run is shorter, it provides a general aerobic training stimulus twice per day instead of once. What this means is that the genes that cause desirable changes, like increased mitochondria or an increase in oxygen-carrying capacity, are activated for a greater total amount of time than if you did one run. So you have a much more sustained pressure on adaptation.

Second, by running doubles, especially after a hard workout, you're now training in a pre-fatigued state. Doing so allows you to access different muscle fibers that you might not normally train, or to push slightly more into the depths of glycogen depletion than would be normal. As a result, you get a slightly different stimulus for adaptation. Research looking into training twice per day versus once for the same total weekly volume has shown that the increases in aerobic enzymes can be potentially greater when doing two bouts of exercise relatively close together.

HOW TO START RUNNING MORE OFTEN

Now that you know what doubles can achieve that singles can't, how do you implement them into your program? The most important factor is determining what the purpose of the double is. Once that's known, then deciding when and how to use a second run is easy. Before we look at some scenarios, it's important to realize that, however you use doubles, you're adding a new stimulus to your training. Keep the pace easy on these new runs, and because most of these secondary runs are so short, you don't need to devote time to your usual pre-and post-run stretches, exercises, etc. Just run, baby!

When the goal of doubling is to enhance recovery, split your mileage for the day as evenly as possible. For example, if you planned an 8-mile day, do two runs of 4 miles each. By splitting it evenly, you minimize fatigue but get a nice even boost of all the good stuff described above twice in one day. For my athletes, we most often schedule recovery doubles like this the day after a hard day. An example would be to have a hard workout on a Tuesday, follow that up with a Wednesday that includes two short runs, do a normal-length single run on Thursday, and another hard workout on Friday. This type of schedule allows for a nice mix of split doubles to enhance recovery while still having some single runs included to maintain general aerobic abilities.

On the other hand, if your goal in doubling is to get a little more bang for your training-adaptation buck, schedule a double for when you'll be a little fatigued. This can be done two ways. First, you can place a second shorter run of 3 to 6 miles the afternoon after a morning hard workout. It's unlikely you'll be fully recovered from the morning workout, so you'll be doing the second run in a slightly pre-fatigued state. Or you can schedule two unevenly split runs so that you have a longer single run in the morning followed by a short double in the afternoon. By scheduling the double this way, you'll not only squeeze out a little more adaptation, but also enhance recovery a bit.

Finally, doubles can be used to prime the pump for workouts or races. In this case, you would want to do the double in the morning before an afternoon workout. The short morning run would serve to prime the body by flushing out the system and manipulating the muscle tension so that you're in a better position physically to run the hard workout in the afternoon. When using this method, keep the run short (between 2 and 4 miles). You can also do this several hours before a race–most easily done for an afternoon or evening race–perhaps with some light strides at the end to top things off.

The key when starting to double is realizing that, like any new training implementation, you have to give yourself time to adapt and adjust to the new schedule. After this adjustment, you'll be on your way to seeing the full benefits and will likely not look back.

What to Expect When You Start Doubling

Adding doubles is a new stimulus for most runners. As with any stimulus, you have to adapt to it before you receive the full benefits. If you're new to doubling, start by adding one double per week for two weeks, then increase to two doubles per week for two weeks. After that, the length of the doubles can be increased.

The first time you add a second run, you'll likely feel slightly more worn down and tired because your body isn't used to running twice a day. The second time should feel slightly easier, and by the third time you double, you should feel adjusted and will start to feel better instead of more fatigued. Like anything, it's a gradual adaptation process, so don't be discouraged after the first run. Keep it short (1–2 miles), as the key is getting your body used to running twice and adjusting your body's rhythm.

Why Two-a-Days Increase Recovery

Increase in blood flow twice per day.

Increase in recovery hormones like human growth hormone.

Change muscle tension and take body through extended range of motion more often, decreasing stiffness and soreness.